Ann Thorac Surg 2009;88:273-275. doi:10.1016/j.athoracsur.2008.11.037
© 2009 The Society of Thoracic Surgeons
Case Reports
Idiopathic Pulmonary Artery Aneurysm Treated With Surgical Correction and Concomitant Coronary Artery Bypass Grafting
George Arnaoutakis, MD*,
Lois Nwakanma, MD,
John Conte, MD
Division of Cardiac Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland
Accepted for publication November 10, 2008.
* Address correspondence to Dr Arnaoutakis, Division of Cardiac Surgery, The Johns Hopkins Medical Institutions, 600 N Wolfe St, 618 Blalock, Baltimore, MD 21287 (Email: gja10{at}jhmi.edu).
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Abstract
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Idiopathic pulmonary artery aneurysm is a rare clinical entity, and therefore the natural course and clinical management are not well established. We present the case of an elderly woman with a symptomatic idiopathic pulmonary artery aneurysm who underwent surgical repair along with simultaneous coronary artery bypass grafting. With long-term follow-up presented in this report, we describe the safety and durability of surgical repair.
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Introduction
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Pulmonary artery aneurysm (PAA) is an uncommon clinical entity, with a reported incidence in large autopsy series of 1 case per 13,700 [1]. PAA can be congenital or acquired, and most cases are associated with other congenital malformations, primary or secondary pulmonary hypertension, vasculitides, infectious agents, or collagen vascular disorders [2]. Idiopathic PAA is a rarer entity, and the natural course and clinical management are not well established. Some recommend surgical correction, whereas others advocate conservative management in asymptomatic patients [3]. The recommendation for surgical intervention has been based on limited experience derived mainly from small case series [4]. Furthermore, patient follow-up in earlier case reports is limited to the early postoperative period [5]. We report an idiopathic PAA repair with concomitant coronary artery bypass grafting (CABG).
A 75-year-old white woman reported chest pain and progressive exertional dyspnea. Her history included hypertension. After a chest roentgenogram performed in 1978, the patient was told she had "vascular pathology," without further work-up. Symptoms developed in 2002, and the workup included a negative result on a stress test, 2-dimensional transthoracic echocardiography, computed tomography (CT) scan of the chest, and left heart catheterization. Echocardiography showed right ventricular (RV) dilatation, with elevated RV systolic pressure to 40 to 50 mm Hg, and mild pulmonic and tricuspid valve insufficiency. The CT showed a 6-cm main PAA without evidence of dissection (Fig 1). The main left and right pulmonary arteries (PAs) were normal caliber based on CT appearance. In the presence of symptoms, the patient was determined to be an appropriate surgical candidate.
Preoperative cardiac catheterization revealed an 80% proximal right coronary artery lesion. Inflammatory and infectious etiologies were ruled out with laboratory testing, including erythrocyte sedimentation rate and C-reactive protein levels within normal limits. Autoantibodies suggestive of collagen vascular disorders were not present. There was no history of arthritis and no evidence of aphthous lesions or other signs consistent with Behçet disease. Plans were therefore undertaken for PAA repair and simultaneous CABG.
Intraoperative transesophageal echocardiogram (TEE) revealed a pulmonary valve annulus diameter of 2.8 cm with central mild pulmonary insufficiency. A patent foramen ovale was noted without shunting. The PA was dilated, with maximal diameter of 7.5 cm. There was no thrombus, infection, or dissection. Using intraoperative Swan-Ganz monitoring, no gradient was detected across the valve. Inspection showed the valve was competent, with 2 normal and 1 dysmorphic leaflets. Despite the single dysmorphic-appearing leaflet, all three leaflets were freely mobile without evidence of stenosis. A saline irrigation test was performed, and there was no leakage across the pulmonary valve. The proximal left and right main PAs were also enlarged to 4 cm.
After median sternotomy, cardiopulmonary bypass was established. The main PA was transected and dissected proximally and distally to expose the pulmonic annulus and main left and right pulmonary branches. Using running 4-0 Prolene suture (Ethicon, Somerville, NJ) a 24-mm Hemashield Dacron graft (Boston Scientific, Natick, MA; DuPont, Wilmington, DE) was anastomosed from the proximal main PA to the left main PA just before its exit from the pericardial sac.
Attention was then directed to the anastomosis of the right main PA. The right main PA anastomosis was created in Y-fashion off the side of the tube graft. Next, through a right atriotomy, a small patent foramen ovale was repaired with running 4-0 Prolene suture. The right coronary artery was bypassed without arresting the heart.
The patient was separated from cardiopulmonary bypass with minimal inotropic support.
Her postoperative course was remarkable for one episode of self-limited atrial fibrillation and a urinary tract infection requiring oral antibiotics. At the last follow-up, the patient was doing well, without symptoms 4 years postoperatively.
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Comment
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This article reports an idiopathic PAA repair with concomitant procedures, with follow-up extending to 4 years [4, 5]. We believe that idiopathic PAA repair in the fashion described may confer durable results. It is possible that her symptoms could have been related to the right coronary artery lesion, although no wall motion abnormality on echocardiography suggests otherwise. Nevertheless, this report demonstrates that simultaneous PAA repair and CABG is feasible.
An additional consideration is the presence of "vascular pathology" for nearly 3 decades. We surmise that the abnormality on the chest roentgenogram was related to PAA enlargement nearly 30 years ago. The principle of LaPlace dictates the basis for surgical recommendations for aneurysms of the systemic circulation. However, being under less pressure, PA risk of rupture should theoretically be less. It is currently not known at which PA diameter the risk of rupture outweighs the risk of the operation. This case suggests that this patient lived with a PAA for at least 30 years without rupture. Only upon the development of symptoms was an operation undertaken. Had this patient been entirely asymptomatic, we would have monitored her with annual CT scans. Serial echocardiography would also have been used to monitor cardiac function. In that scenario, indications for surgical repair would have been RV dysfunction, moderate to severe valvular incompetence, progressive aneurysmal dilatation, or the development of symptoms.
We believe the aneurysm developed due to a variant of poststenotic dilation. High velocity flow caused by the dysmorphic valve leaflet led to the PA dilation. On pathologic examination, medial degeneration was noted but no cystic component. This finding supports our suspicion of chronic degenerative wall stress leading to aneurysm formation. Because the pulmonic valve was deemed sufficiently competent and nonstenotic, we repaired the aneurysm without intervening on the valve itself. Given this patient's age, the likelihood of developing problems later in life secondary to mild pulmonary regurgitation was low and did not justify the risks associated with valve replacement. Also, because we believe the aneurysm was related to turbulent flow passing through the dysmorphic leaflet, replacing the artery with a Dacron graft virtually eliminated any risks of aneurysm recurrence. Although the elevation in RV systolic pressure may have been related to longstanding mild pulmonary insufficiency, she did not demonstrate any impaired RV systolic function, and so we did not think this was an indication to replace the valve.
The approach to surgical repair has also been debated. Many authors advocate a plication technique, restoring the diameter to normal size by excluding the anterior portion of the PA [4]. We performed the reconstruction using a tubular graft because we believe that complete reconstruction can be accomplished with minimal risk and may offer superior long-term results.
In summary, idiopathic PAA is a rare, potentially life-threatening condition in the setting of rupture or dissection. We recommend elective surgical repair in the setting of symptoms or evidence of RV dysfunction, ideally before impending RV failure. When performed in this manner, long-term results appear satisfactory. Furthermore, low-risk additional cardiac surgical procedures can be performed simultaneously without adding risk to the operation.
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References
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- Deterling R, Claggett O. Aneurysm of the pulmonary artery: review of the literature and report of a case Am Heart J 1947;34:471-499.[Medline]
- Bartter T, Irwin RS, Nash G. Aneurysms of the pulmonary arteries Chest 1988;94:1065-1075.[Free Full Text]
- Vural AH, Turk T, Ata Y, et al. Idiopathic asymptomatic main pulmonary artery aneurysm: surgery or conservative management?. A case report. Heart Surg Forum 2007;10:E273-E275.[Medline]
- Veldtman GR, Dearani JA, Warnes CA. Low pressure giant pulmonary artery aneurysms in the adult: natural history and management strategies Heart 2003;89:1067-1070.[Abstract/Free Full Text]
- Deb SJ, Zehr KJ, Shields RC. Idiopathic pulmonary artery aneurysm Ann Thorac Surg 2005;80:1500-1502.[Abstract/Free Full Text]
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Abstract
Introduction
